Not exactly.
According to the chart the fuselage for Scale may not exceed 1" thickness, period. There is no allowance for doublers, etc. However you decide to construct the fuselage the end result may only be 1" wide at its widest point.
(Clip)
What "chart" for Scale are you looking at? There is no "chart" that defines any fuselage widths in the Control Line Scale rule book. In the Control Line General rule book, there is a chart that defines "Profile Fuselage Width" for the various profile control line events. For Scale, that chart shows the "Maximum Fuselage Width" to be "1 inch" and the "Max Width of Additional Reinforcements" for "Engine Mount Vertical" to be "Mounting Lugs Plus 1/2 Inch" and for "Horizontal" to be "1/2 inch"
So, there is an "allowance for doublers, etc" and there are portions of the fuselage and/or nacelles that can exceed 1" wide.
If we are going to go by the CL Scale rules for Profile Fuselages, we need to look at Paragraph 5.2 of the scale rules which does not conflict with the Control Line General rules for profile fuselages use in Control Line Scale.
"The maximum width for profile fuselages and nacelles will be on (1.0) inches. For upright and inverted engine(s) the maximum reinforced fuselage and/or nacelle width may be one half (1/2) inch wider than the engine mounting lugs. The maximum width of the reinforced fuselage and/or nacelle of horizontally mounted engine(s) will be one and one half (1.50) inches. Additional reinforcement [may] be made in the engine/motor area of the fuselage extending from the front of the fuselage to a point twenty five percent (25%) of the maximum wing chord aft of the leading edge of the wing. For engine(s)/motor(s) mounted in nacelle(s) the maximum reinforcement length will be from the front of the nacelle to a point twenty five percent (25%) of the maximum wing chord length aft of the wing leading edge at the nacelle location. For multiengine models the width of nose section of the fuselage may be increased to one and on half (1.5) inches extending from the front of the fuselage to a point twenty five percent (25%) of the maximum wing [chord] aft of the leading edge of the wing."
Note: The brackets - [ ] - shown above are to correct typographical errors in the rule book. [may] is shown to replace the incorrect word "many". [chord] is shown to replace the incorrect word "cord".
A profile scale model of the Do 335 presents interesting design challenges. First, a decision needs to be made if the aft engine will be mounted in the scale position which is just behind the wing trailing edge with the requisite long shaft to the rear propeller or if the aft engine will be located at the very rear of the fuselage somehow, somewhere between the horizontal tail sections. If the engines/motors are not larger than 0.20 cu in or even 0.25 cu in (or the battery powered equivalents), then the 1" maximum width to mount these power plants would seem to be enough to provide enough structure for these power plants. If larger power plants are planned, then some additional doublers/reinforcement might be used around the area of the motor mounts but would probably not be necessary unless rather large engines are used like 0.45 cu in or larger. (Then you are probably going to have a HUGE Do 335.) That would create a rather unsightly "bulge" on the fuselage for the mid-engine approach and would complicate how to mount the engine if it is mounted in the tail section between the horizontal tail sections.
Keith